Compound latch unit



Jun@ 28 B955 W. Y. FARNSWQRTH COMPOUND LATCH UNIT Filed July 14, 1952jam@ 2&9 lg W, y. g-"Awmgwgmwz ZJELZ@ COMPOUND LATCH UNIT Filed July 14,l952 3 SheetsSheet 2 rmfwir Fume 28, E955 Filed July 14, 1952 W. Y.FARNSWORTH COMPOUND LATCH UNITv 3 Sheets-Sheet 3 United States Patent2,711,920 coMPoUND LATCH UNIT William Y. Farnsworth, Redwood City,Calif., assigner to Schlage Lock Company, a corporation Application July14, 1952, Serial No. 298,703

' -3 Claims. (Cl. 292-169) My invention relates primarily to lock setsfor doors and is especially concerned with a latch unit for use in alock set of the type shown in Walter R. Schlage Patent No. 2,293,856,for example, as well as in other types of locks.

In the manufacture of a lock set for general installation on a doormounted to swing on hinges with respect to a door jamb, there is alwaysan allowance made for the necessary clearance between the edge of thedoor and the'door jamb. Usually, the bolt is a latch bolt beveled alongone face so that when the door is being closed the leading, beveledportion of the latch bolt strikes against the strike plate on the doorjamb. This depresses the latch bolt against spring urgency as the doorapproaches closed position. The latch bolt then, under the'urgency ofthe just compressed spring, is projected into a recess partly defined bythe strike plate and arranged in the door jamb. The amount of lengthwisemovement or throw of the latch bolt with respect to the strike plate ordoor jamb is selected as an amount which will not require too muchrotation of the operating handle or knob for easy functioning, yet whichwill permit'the latch bolt to project sufficiently into the strike boxso as to afford adequate security. In some installations', particularlyin connection with wooden doors and jambs and particularly in instanceswherein the lumber utilized is not thoroughly'dried when erected, theinitial clearance between the edge of the door and the door jambincreases, due to warpage and shrinkage of the door and jamb material,to anv amount which is nearly as great as the stroke or throw of thelatch bolt. This reduces the amount of the latch bolt housed within thestrike box and substantially reduces the security of the lock. Lock setscommercially supplied have a relatively standard stroke. It is difficultor impossible to increase the amount of stroke in a commercial lock setwithout either completely redesigning such set or making other drasticchanges thereto.

It is therefore an object of my invention to provide a compound latchunit as a replacement for the stand ard latch 'unit of a commercial lockset having a predetermined stroke, to afford a latch bolt stroke orthrow` of a greater amount.

Another object of my invention is to provide a latch unit affording anAincreased amount of latch boltmovementffor a standard amount ofactuator movement.

AV still further object of `my invention is to provide a compound latchunit easily interchangeable'with latch boltiinits presently availableand of the` type shown in4 2,711,920 Patented June 28, 1955 rice morethan usual stroke with a latch bolt having more than the customarystroke.

A still further object of my invention is to provide a compound latchunit interchangeable with a regular latch unit so that by the merechange of units a lock set can be adapted to a door installation havingeither normal or abnormal clearance between the door and th jamb.

A still further object of my invention is to provide in general animproved compound latch unit.

Other objects, together witth the foregoing, are attained in theembodiment of my invention, described in the accompanying descriptionand illustrated in the ac-l companying drawings in which:

Figure l is a cross section through a compound latch unit according tomy invention with a portion of an associated lock unit incorporatedtherewith, portions of the figure being broken away to reduce its size,and parts of the structure being shown in side elevation. The section ofFigure 1 is on a vertical median plane.

Figure 2 is a cross section, the plane of which is indicated by the line22 of Figure l, a portion of the structure being broken away to reducethe size of the ligure and to show subjacent parts.

Figure 3 is a cross section, the plane of which is indicated by the line3--3 of Figure 1.

Figure 4 is a cross section, the plane of which is indicated by the line4 4 of Figure l.

Figure 5 is a side elevation approximately duplicating Figure 1 but withadditional portions being broken away and showing the latch bolt in aretracted rather than an extended position.

Figure 6 is a cross section substantially like Figures l dicated by theline 7--7 of Figure 6.

Figure 9 is a cross section, similar to Figure l, but

showing the modified form of device.

Figure l0 is a cross section, somewhat similar to Figure 3, but showingthe modilied form of device, the plane of section being indicated by theline 10-10 of' Figure 8.

In the usual installation of a lock set there is provided a door panel 6(Figures l, 5, 6 and 7), adapted to swing with relationship to a doorjamb 7 (Figure 7). The door panel 6, usually of wood, is pierced by atransverse or through bore in which an actuator casing 8 is disposed.Knobs or other actuating instrumentalities operate a rotary spindle 9about transverse axis 11 in either direction of rotation. The spindle 9on its inner end is pro vided with a pair of projections 12 and 13normally resting against abutting shoulders 16 and 17 on a slider 18confined to rectilinear translation in an actuator frame 19 situatedwithin the casing 8. The slider 18 is urged toward the edgeZl of thedoor panel 6 by a pair of coiled springs 22 and 23 arranged to abutagainst ledges 24 on a clip 26, forming part of the frame 19.

The shoulders 16 and 17 on the slider 1S are united .with actuator jaws27 and 28 disposed opposite each other on the slider and translate in arectilinear path with the slider. When the lock set is not actuated, thejaws 27 and 28 are in their left hand position (as seen in Figure l) andwhen the spindle 9 is rotated-in either direction, the jaws 27 and 2Sare moved in a right hand direction (as seen in Figure l) and overcomethe urgency of the springs 22 and 23. Thus upon rotation of the spindlethe jaws 27 and 28 are advanced and retracted in a rectilinear pathsubstantially from one edge of the casing 8 toward the central portionthereof. The standard amount of travel of the retractor is indicated bythe arrow 31 in Figure l. The unit as so far described is substantiallystandard.

ln a normal installation, the door panel 6 is also provided with acircular cylindrical housing 32 having,

on its inner end a frame 33 with outturned prongs34 designed tointerengage with the casing S with a lateral sliding motion to afford arm interconnection between the casing and the housing. At its oppositeend, the crcular cylindrical housing 32 is formed with an outwardlydirected flange 36 received between a face plate 37 and a backing plate38, recessed in the edge 21 of the door. A pair of fasteners such asscrews 39 serve to hold the face plate 37 and the circular cylindricalhousing 32 in the appropriate aperture or bore provided in the door. Thescrews 39 serve to conne the housing 32 against longitudinal movementjust as the interconnection between the prongs 34 and the actuatorcasing 8 confine the housing 32 against rotary movement. Preferably themounting is such that the central longitudinal axis 4l. of the housing32 intersects the transverse axis 11 of the actuator unit and normallythe axis 41 is disposed substantially midway between the sides of thedoor 6.

As shown especially in Figure 7, there is installed in the door jamb 7 astrike plate 42 bounding the edges of a strike box 433 comprised of aseparate enclosing structure which serves as a lining for a depressionor hole or recess in the door jamb. Sometimes the strike box is omittedbut the strike plate remains. The location of the strike plate 42 issubstantially in registry with the location of the face plate 37 whenthe door is closed.

Mounted for reciprocation in a predetermined path in the circularcylindrical housing 32 and in the direction of the central axis 41 is alatch bolt 46. rl`his latch bolt is substantially standard as to itsexternal appearance in that it includes a relatively dat face 47 and hasan adjacent cam curved face 48 both cut from a generally circularcylindrical body 49 symmetrical about the axis 41. The body 49 of thelatch bolt is somewhat longer than previous practice and includesextensions 51 bearing against the inside surface of the housing 32 toafford a substantial support for the latch bolt not only when it isprojected as shown in Figure l but also when it is retracted as shown inFigure 5. Preferably the movement of translation of the latch bolt isgreater than the movement of the retracting jaws 27 and 28 and asindicated by the arrow 50 (Figure l) is approximately twice that of theactuator.

To assist in affording the desired increased movement I provide thelatch bolt with a special latch bolt stud '52. This is primarily a hardbar having reduced and enlarged portions designed to cooperate with anoff Center hole drilled in the deformable material of the latch bolt 46.The arrangement is such that when the bolt stud 52 is driven into thepreviously drilled hole in the latch bolt, some of the relatively softmaterial of the latch bolt is displaced into the reduced portion of thebolt stud and forms interlocking lugs 53. Once the assembly has beenmade, the latch bolt stud and the latch bolt are in effect an integralunit.

The latch bolt studr 52 at its inboard end is provided with a transversepin 56 disposed to one side of the axis 41.in one aspect (Figure l) andalso disposed slightly to one side of the central axis 41 from anotheraspect (Figure 2). The pin 56 is moved by forces exerted eccentricallyon the pin but the extensions 51 of the latch bolt serve to withstandsuch eccentric loading.

In order to actuate the pin 56 and the latch-bolt, I provide a compoundlever 57. This lever is essentially a plate provided adjacent one endwith a pin 58 journaled in an appropriate bore formed in a boss 59supported on the housing 32, there being provided an indentation 61therein especially to serveas a base, the boss 59 in position, the rivetbeing a little loose Vso Zij that the boss 59 can be rotated tofacilitate assembling the fulcrum pin 58 in the mounting boss 59. Theopposite end of the compound lever 57 is provided with a peripheralnotch 63 designed to interengage with the pin 56 with some lost motion.

Also projecting from the compound lever 57 is a pin 64 parallel to thepins 56 and 58 and disposed between them. The distance radially of thepin 64 from thc fulcrum pin S8 is less thanl (usually half) the distanceof the pin 56 from the fulcrumj pin 58 in any position ol the pin 56.Engaged with the pin 64 is a retractor bar 66 having an elongatedaperture 67 therein for that purpose. vThe other end of the retractorbar 66 extends through an opening in the housing 32 and terminates in unenlarged head 68 having a standard contour and lying immediately behindthe jaws 27 and 28.

With this arrangement, when the spindle 9 is rotated in either directionand the slide 18 is consequently translated or retracted, the jaws 27and 28 engaging the head 63 translate the retractor bar 66 and, aftertaking up any lost motion, rotate the compound lever 57 about thefulcrum pin S8 as an axis. The engagement of the wall t of the notch 63with the pin 56 then produces a corresponding but greatly augmentedrectilinear retraction or tr mslation of the latch bolt 46. The amountof translation of the latch bolt, as indicated by the arrow S0, issubstantially twice the amount of translation of the head l 68 asindicated by the arrow 31. There are thus provided A riversa hoidsmeansfor producing an augmented motion of the latch belt for a standardamount of motion of the retractor bar or of the knob spindle 9.

When the door is moved to a closed position, the latch bolt 46 isdepressed as the cam surface 48 contacts the strike plate 42. The pin 56then moves to take -up the lost motion in the notch 63, and rotates thecompound lever 57, the pin 64 taking up the lost motion with the slot 67and the retractor bar 66 being moved inwardly away from the jaws 27 and28 as far as necessary. With this structure there is provided a latchbolt and its housing externally almost indistinguishable from and freelyinterchangeable with a standard latch bolt and housing. At

their interengaging portions, the compound latch bolt unit and theactuator unit t together in exactly the standard fashion, although thereis provided a greatly augmented travel of the latch bolt itself with astandard rotation of the spindle.

The structure as so far described serves well as a plain latch boltunit, and is shown slightly modified expressly for such service inFigures 8, 9 and l0. But often it is desired to have a dead latchfunction in addition so that the latch bolt cannot be externallydepressed when thc door is closed. There is consequently provided a stoplever 71 having a rocker portion 72 in abutment with the frame 33 withinthe housing 32 and having extended and apertured bifurcations 78 and 79.These surround a'pair of pins 81 and 82 extending inwardly of thehousing 32 from their mounting on the rear wall 83 thereof and on theframe 33. To hold the stop lever 71 in position and particularly to urgethe bifurcat'ed portions towardv thc rear wall of the housing, a pair ofcompression springs 84 and 86 surround the pins and bear against aspring lever 87. A foot 88 on the spring lever 87 bears against theframe 33 within the housing and has a pair of lugs 89 and 91 pressingagainst the stop lever 71. -The force of the longitudinal springs 84 and86 on the spring lever 87 is thus transmitted throughthe lugs 89 and 91to the stop' When the parts are in the position. described, the latchbolt 46 can be externally forced into the housing 32 only in the amountof the lost motion between the end of the latch bolt stud and the tongue92. It is impossible for the latch bolt to be translated sufficiently byexternal pressure, when the door is closed, to unlatch the door.

So that the latch bolt can be retracted under appropriate circumstances;that is, when the actuating unit is operated by rotation of the spindle9 or when the open door is being closed, there is provided a means forpreventing the dogging operation of the tongue 92 in the path of thelatch bolt stud. This is accomplished by moving the tongue out ofdogging position into another extreme position out of the path of thelatch bolt stud. Upon operation of the spindle 9, the retractor bar 66is retracted in the usual way and rotates the compound lever 57. On itsperiphery near the notch 63 the compound lever is provided with a cam 93designed to ride under and against a cam follower 94 formed as part ofand downturned slightly from the main body of the stop lever 71.

While there may be slight clearance between the walls of the notch 63and the pin 56 and while there may be slight clearance between the ca m93 and the cam follower 94, the relationship is such that upon initialoperation of the retractor bar 66 and initial rotation of the compoundlever 57, the lost motion is taken up and upon further rotation of thecompound lever, the cam 93 acts to lift the cam follower 94. This rocksthe stop lever 71 and lifts the tongue 92 out of the path of the latchbolt stud 52. The arrangement is such that the tongue 92 just liftsclear of the translating end of the latch bolt so that further movementof the retractor bar 66 finally moves the latch bolt 46 into fullyretracted position.

When the spindle 9 is released, the latch bolt is projected again underthe urgency of the spring 86 pressing against the inner face of thelatch bolt. The other parts go through a reverse cycle of operation andthe cam follower 94 follows the cam 93 as the compound lever rotatescounterelockwise. dogged as the tongue 92 occupies its extreme positionbehind the latch bolt stud 52. In this fashion, while the latch bolt isnormally deadlocked or dogged in deadlocked position when the door isclosed, the operation of the spindle 9 serves to undog the deadlockedlatch bolt r for normal operation.

A. similar effect is produced by a dead latching plunger 101 projectingthrough the same aperture in the face plate through which the latch bolt46 projects. The plunger 101 is in effect a bar confined substantiallyto rectilinear translation in a path parallel to but alongside of theaxis 41. The plunger has a foot 102 disposed behind the main body of thelatch bolt 46, and terminates in a stud 103 disposed within the spring84 and enlarged by a collar` 104 against which the spring presses. Thecollar is distinguished from the remaining part of the plunger by agroove 106 in which a fork 107 is fitted. This fork is on the leadingend of a bar 108 extending longitudinally of the housing 32 andsupported and guided in an appropriate aperture in the rear wall 83 andframe 33. The bar 108 intermediate its ends is contoured especially asshown in Figures 5 and 6, to provide an inclined cam 109 disposed toride under the tongue 92 of the stop lever 71.

When the door is in closed position, as shown in Figure 7, the plunger101 is held in its inner, longitudinal position by the strike plate 42on the door jamb 7. When the plunger moves into its inner position, itnot only comw presses the spring 84 but also, by reason of theinterconnection of the fork 107 in the groove between the body of theplunger and the collar 104, it moves the bar 108 so that the cam 109rides out from under the tongue 92. This permits the tongue 92 to dropinto its lowermost position in the path of depression of the latch boltstud 52. With the tongue in this position, the lock is dead- The latchbolt unit is again 6 latched or deadlocked in that the latch boltisdogged by' the tongue of the rocker lever 71.

When the door is in open position and there is no external force exertedagainst the plunger 101, the expanded spring 84 urges the plunger 101outwardly until the foot 102 abuts the inner surface of the latch bolt46. This outward motion is also imparted to the bar 108. Consequentlythe bar 108 moves the cam 109 under the tongue 92 and lifts it from itslower dogging position into its upper position out of the path of theend of the latch bolt stud 52. The latch bolt 46 is thereby freed fordepression into the housing 32. The translational movement of theplunger 101 is in an augmented amount to correspond with the augmentedmovement of the latch bolt. The extra travel is utilized in thedeadlocking or dogging operation by virtue of a correspondingproportioning of the cam surfaces and cam followers to produce thedesired result.

As mentioned above, the structure is slightly modified if thedeadlatching function is not required. As shown in Figures 8, 9 and l0,the housing 132 is, as before, concentric with an axis 133 and serves asa mounting for a retractor bar 134 identical with the retractor bar 66and similarly connected to a compound lever 136 identical with thecompound lever 57. A latch bolt stud 137, like the latch bolt stud 52joins the compound levers to a latch bolt 138. This is generally similarto the latch bolt 46 but is not identical therewith.

The latch bolt 138 is formed from circular stock, has a central channel139 to accommodate the compound lever and its attendant mechanism and isprovided with a shoulder 141 abutting a face plate 142 having anaperture 143 therein only large enough for the latch bolt. A pair ofsprings 144 and 146 surround pins 147 and 148 mounted on the housing 132and press against the end wail 149 of the housing and against the latchbolt 138, being received in circular bores 151 and 152 for that purpose.

Since it is desired that the parts be as nearly standard as possible,the opening 153 in the wall 149 is of sufficient width to receive a bar108 (Figure 4) even though that part is not used in the absence of thedeadlatching function. Excess lateral play might thus be permittedbetween the retractor 134 and the housing 132. To obviate that adversefactor, a spacer bar 154 is disposed in the opening 153 alongside theretractor 134 to occupy any excess space. The spacer bar has a turnedcircular head 156 disposed in the bore 151 between the latch bolt 138and the spring 144 and consequently is approximately retained for travelin unison with the retractor 134. The operation of this modification issubstantially the same as previously described except that there is nodeadlatching function.

What is claimed is:

l. A latch unit comprising a housing, a latch bolt mounted in saidhousing for reciprocation along an axis from a projected positionprojecting outwardly from said housing to an inner depressed positionsubstantially within said housing, a latch bar reciprocably supported insaid housing for movement along said axis, a lever swingably secured atone end to said housing, means connecting the opposite end of said leverto said latch bolt for depressing the latter upon inward swinging ofsaid lever, means on said lever intermediate said ends and connectedwith said latch bar for so swinging said lever upon inward movement ofsaid latch bar, whereby the translatory movement of said latch bolt isgreater than that of said latch bar, a dogging member, means urging saidmember to a position in the path of travel of said latch bolt when thelatter is in projected position to prevent depression thereof, and meanson said lever engageable with said member upon inward swinging of saidlever for moving said member to a position out of said path permittingdepression of said latch bolt.

2. A latch unit comprising a housing, a latch bolt mounted in saidhousing for reciprocation along an axis from a projected positionprojecting outwardly from said housing to an inner depressed positionsubstantially Within said housing, a latch bar reciprocably supported insaid housing for movement along said axis, a lever swingably secured atone end to said housing, means connecting the opposite end of said leverto said latch bolt for depressing the latter upon inward swinging ofsaid lever, means on said lever intermediate said ends and connectedwith said latch bar for so swinging said lever upon inward movement ofsaid latch bar, whereby the translatory movement of said latch bolt isgreater than that of said latch bar, a clogging member, means urgingsaid member to a position in the path of travel of said latch bolt whenthe latter is in projected position to pre vent depression thereof, andmeans on said lever engageable with said member upon inward swinging ofsaid lever for moving said member to a position out of said pathpermitting depression of said latch bolt, said last mentioned meanscomprising a cam integral with said lever.

3. A latch unit comprising a housing, a latch bolt mounted in saidhousing for reciprocation along an axis from a projected positionprojecting outwardly from said housing to an inner depressed positionsubstantially within said housing, a latch bar reciprocably supported insaid housing for movement along said axis, a lever swingably secured atone end to said housing, means connecting the opposite end of said leverto said latch bolt for depressing the latter upon inward swinging ofsaid lever, means on said lever intermediate said ends and connectedwith said latch bar for so swingingl said lever upon inward movement ofsaid latch bar, whereby the translatory movement of said latch bolt isgreater than that of said latch bar, a dogging member, means urging saidmember to a position in the path of travel of said latch bolt when thelatter is in projected position to prevent depression thereof, adeadbolt reciprocably mounted alongside said latch bolt, means carriedby said deadbolt for swinging said dogging member to a position out ofthe path of travel of said latch bolt when said deadbolt is projected.

References Cited in the file of this patent UNITED STATES PATENTS1,876,081 Schlage Sept. 6, 1932 2,219,740 Hillgren Oct. 29, 19402,250,727 Schlage July 29, 1941 2,293,645 Falk Aug, 18, 1942 2,613,094Schlage Oct. 7, 1952

